60 Bulletin No. 207. 



Rabbits: Rabbits were susceptible to B. botulinus when 

 administered subcutaneously. 0.5 cc. of broth culture of B. 

 botulinus proved fatal in 20 to 48 hours. Similar amounts by 

 the mouth did not cause evident symptoms. 



Chickens: Chickens apparently possess a tolerance to B. 

 botulinus administered both by the mouth and subcutaneously. 

 On September 30th, 1916, six chickens were placed in a house 

 with a false elevated floor (Fig. 7). From September 30th 

 to October 9th these birds received at intervals the contents 

 of 4 corn agar slants of B. botulinus and 45 cc. of broth cul- 

 ture of B. botulinus. During the course of the following 35 

 days they were fed 268 cc. of pork broth cultures of B. botu- 

 linus and 5 cc. of gelatin cultures of the organism. The cul- 

 tures were mixed in cornmeal and fed immediately. The feed- 

 ing of these large amounts of toxin produced no noticeable 

 effect upon the chickens. Subcutaneous injections of 5 cc. 

 unaltered broth cultures of B. botulinus, repeated in 5 days, 

 produced only transitory symptoms in mature chickens. 



The results of feeding and injecting B. botulinus into an- 

 imals corroborate to a degree the observations of Buckley and 

 Shippen and incidentally suggest the presence of an etiologic 

 entity in some outbreaks of forage poisoning in horses. It is evi- 

 dent from our observations that B. botulinus is pathogenic for 

 horses and mules. The infection in these animals after the inges- 

 tion of unaltered cultures of B. botulinus presents a striking 

 clinical analogy to forage poisoning. This analogy is further 

 suggested by gross anatomic alterations. 



Horses proved equally as susceptible to B. botulinus as 

 the smaller laboratory animals; indeed, it would seem that 

 horses and mules are more susceptible than guinea pigs, in 

 proportion to body weight, to small amounts of the toxin. 

 There is no characteristic clinical analogy between the pera- 

 cute cases of botulism artificially induced in horses and those 

 observed in forage poisoning, since no definite symptoms oc- 

 cur in the former cases. In animals more mildly intoxicated, 

 as shown by several of our experimental horses, clinical mani- 

 festations were observed not unlike the symptoms displayed 



